Postlab quiz 5 Flashcards
What is a neuron refered to as (video)
multipolar neuron (normal)
What is used in the video to dtermine resting membrane potential
electrode attached to voltmeter
What instrument did we use in lab
ocilloscope
depolarization =
stimulation
hyper polarization =
inhibition
RMP in podcast
-65 to -95mV
What is distrurbed when stimulus takes place
RMP
Na+ channels: The channel is closed at this point
RMP
Na+ channels: The channel is opened by this
depolarization (AP)
Na+ channels: the channel is inativiated during this period
refractory period (absolute)
Na+ channels: How is the channel inactivated
opening blocked by protein
Na+ channels: These are this type of channel
voltage gated
What opens voltage gated channels
ambient voltage
when is threshold
-50 mV
What is the top of the spike in the podcast
+30Mv
What resets RMP
Na/K pumps
milliseconds per AP
4 mS
AP frequency is determined by
strength of stimulus
Strong stimuli are felt more strongly because of this
the rate/frequency of the AP
During an absolute RP this occurs
inactivation of Na+ channels
During a relative Rp this occurs
hyperpolarizaition due to efflux of K+
This is needed to generate a AP during relative RP
greater than normal strength of stimulus
These types of neurons are mylinated
motor
sensory
rate of impulse conduction mylinated vs unmylinated
300 m/s to 1 m/s
Spatial summation:
occurs when excitatory potentials from many different presynaptic neurons cause the postsynaptic neuron to reach its threshold and fire.
Temporal summation:
occurs when a single presynaptic neuron fires many times in succession, causing the postsynaptic neuron to reach its threshold and fire.
unidirectional propagation
AP can only move in one way due to absolute refractory period (can move in either way to start)
Chronaxie time
minimum time required for electrical current that is 2x the strength of the rheobase to stimulate neuron
What does chronaxie time measure
excitability
rheobase voltage
lowest intensity which just stimulated nerves
Axis of the graph shown in lab-lec
Y = stimulus strength X = time
Shape of line on the graph shown in lab-lec
exponentially flattening negative slope
What are the names of the two strength of stimulus lines on the graph shown in lab-lec (bottom-top)
Rheobase
Chronaxie
What does temporal summation allow
allows for the post-synaptic neuron to reach threshold faster
chronaxie time is dependent on this
density of voltage gated Na+ channels on a cell
Temporal summation uses this to generate a response in the post-synaptic cell
high frequency AP that overlap and summate with each other
temporal summation is generated by this many neurons
1
spatial summation is generated by this many neurons
many
These are examples of excitable cells
neurons
muscles
T/F: some synaptic transmissions are inhibitory
T, post-synaptic cell is hyperpolarized
open ligand gated K+ channels
Two major physiologic properties of neurons
irritability
conductivity
Irritability is
the ability to respond to stimuli and conver them into nerve impulses
conductivity is
the ability to transmit an impulse
This establishes RMP
Na+/K+ pumps
These are the main cause of the negative charge inside of the cell
intracellular proteins
The AP follows this law
All-or-none law
For this lab we would have used these two tools
electronic stimulator
oscilloscope
The action potential on the screen reflects this
the action potentials of many neurons in the nerve bundle
T/F: all of the neurons are always stimulated if an action potential is generated
F
How does mechanical stimulation create an action potential
pressure opens Na+ channels which begins depolarization of the cell
How does thermal stimulation create an action potential
Increases kinetic energy in ions allowing for faster diffusion
how does added NaCl stimulate a action potential
increases the concentration gradient of Na+ outside the cell leading to faster diffusion
How does HCl stimulate an action potential
Acid denatures the channel proteins
How does ether effect nerve transmission
Its a paralyzer that blocks acetylcholine receptors on the post-synaptic neuron/cell
How does curare effect nerve transmission
blocks acetylcholine receptors on the post-synaptic neuron/cell
What two aspects of the nerve effect conduction velocity
diameter
myelination
What is pain asymbolia
congenital insensitivity to pain with anhydrosis (CPA)
What does pain asymbolia cause (3)
inability to feel pain and temperature
accidental self-injury leading to spontaneous amputation
heal slowly from skin/bone injuries
What are some examples of spontaneous amputation
biting tongue, lips, and fingers
What causes pain asympolia
autosomal recessive gene mutation
The autosomal recessive gene muation in pain asymbolia leads to this (3)
receptory or sensory neurons cannot transmit signals for growth
apoptosis of neurons
loss of sensory neurons and neurons to sweat glands
When does pain asymbolia appear
at birth or during infancy
anhydrosis
decreased or absense of sweating
Signs and symptoms of pain asymbolia (8)
anhydrosis recurrent high fever seizures from high temp thick, leathery skin on palms misshapen findernails/toenails areas on scalp with no hair growth weak muscles when young, that can become stronger with age emotional instability
Treatment for pain asymbolia (4)
no cure
management of symptoms
prevention of injury
occupational therapy
6 muscles of the eye
Superior/inferior rectus
lateral/medial rectus
suberior/inferior oblique
Layers of the eye outside to in
Sclera
choroid
retina
The choroid is coated in this
melanin to prevent after images
Rods are responsible for this
dark vs light
cones are responsible for this
detail and color vision
This part of the eye is an extension of the brain
retina
this part of the eye contains all of the rods and cones
retina
What is the back portion of the eye by the optic nerve called
optic disk
There is no vision or blind spot here
optic disk
Layers of the eye through which light passes (out to in)
cornea
pupil
lens
retina
colored portion of the eye
iris
this is in the middle of the iris
pupil
What helps us focus, and what is it made of
lens
protein
These attach the lens to the ciliary body
zonular fibers
What are the two chambers of the eye, relative to this structure
anterior chamber (infront) posterior chamber (behind) iris
This is in the anterior cavity and maintains the shape of the cornea
aqueous humor
This is the name of the fluid behind the lens, and has this physical property
vitreous humor
gel like to maintain shape behind the lens
T/F: the cornea is not a type of lens
F, its shape defracts lights towards the midline
If the object is close the lens tends to be
thicker
if the object is far the lens tends to be
flatter
accomadation is this process
the process by which we regulate the thickness of the lens
This ciliary muscle is this type of muscle
sphincter
The ciliary muscle is reponsablie for this
adjusting the conformation of the lens
Relaxation of the ciliary muscle does this to the lens
flattens
constrictuion of the ciliary muscle does this
makes the lens fatter
T/F:Looking at close objects far away fatigues the eye
F, close objects fatigue the eye
This is typically concidered far away for vision
15ft
The areas of greatest visual acuity occur at these 2 locations. These receptors are most present here
fovea centralis
macula lutea
cones
The iris does this
limits the amount of light that enters the eye
The iris is composed of these two types of muscles
radially and circulalry arranged smooth muscle fibers
Contraction of the radial muscles of the iris does this
opens (diolates) iris to allow more light in
circular muscles contracting int he iris do this
shrink the pupil allowing less light inot the eye
This nerve will constrict the radial muscles of the eye
postganglionic sympathetic axon from the superior cervical ganglion
this nerve will constrict the circular muscles of the eye
postganglionic parasympathetic axon from the oculomotor nerve
This happens to the image as it passes through the strucutres of the eye
its is flipped upside down, and left to right
Emmetropia =
normal vision
rays focus on retina
Myopia =
nearsightedness
eye is to large
rays focus infront of the retina
What corrects myopia
concave lens
Hyperopia =
farsightedness
eye is to small
rays focus behind retina
What corrects hyperopia
convex lens
Astigmatism =
cornea is unevenly curved
rays do not focus
This causes patches of vision in focus and out of focus
astigmatism
What corrects astigmatism
uneven lens
This is used to discribe the direction in which the correction should be made for astigmatism
cylinder
Rods are most dense here
in the edges of the retina
cones are most dense here
fovea centralis
The cylinder discribes distortions in astigmatism at these points
distinct angles from the center of vision
cones use this to transmit detail
temporal summation
temporal summation requires this (eye)
higher light intensity
Rods use this to transmit signals
spatial summation
spatial summation requires this (eye)
lower light intensity
amacrine cells appear here
between bi-polar and ganglion cells
horizontal cells appear here
between photoreceptor and bi-polar cells
Amacrine and horizontal cells do this
modify synapses to enhance contrast associated with vison
Fibers of the optic nerve are formed by this
axons of ganglion cells
On this visible light spectrum red is here
700
on the viable light spectrum violet is here
400
ROYGBIV =
red orange yellow green blue indigo violet
Three types of cones
S (blue) cone
M (green) cone
L (red) cone
missing one of these types of cones is a condtion called
color blind
This test, tests for color blindness
ishihara test
The negative image test shows us this about photoreceptors
they adapt to stimuli
shows us the chemistry of rods and cones
These are the color compensations for a negative image test (3)
black -> white
Red -> green
blue -> yellow
This allows us to create impulses
photo-pigments
